Method and apparatus for forming helical springs and the like



K. D. BROWN Nov. 18, 1969 METHOD AND APPARATUS FOR FORMING HELICALSPRINGS AND THE LIKE 6 Sheets-Sheet 1 Filed Oct. 21, 1965 INVENTOR.Kenard D. Brown I i g o 2 BY jfi ATTORNEYS Nov. 18, 1969 K. D. BROWN3,478,408

METHOD AND APPARATUS FOR FORMING HELICAL SPRINGS AND THE LIKE Filed Oct.21, 1965 6 Sheets-Sheet 2 IF 9- Fig.6

EELS/-70 INVENTOR. 70 Kenard D Brown Tig-IO ATTORNEYS Nov. 18, 1969 K.D. BROWN 3,478,408

METHOD AND APPARATUS FOR FORMING HELIGAL SPRINGS AND THE LIKE Filed001;. 21, 1965 6 Sheets-Sheet 5 12 INVENTOR. -E- Kenard D. BrownATTORNEYS Nov. 18, 1969 K. D. BROWN 3,478,408

METHOD AND APPARATUS FOR FORMING HELICAL SPRINGS AND THE LIKE 6Sheets-Sheet 4 Filed Oct. 21, 19 65 IN VEN TOR.

KENARD D. BROWN ATTORNEYS Nov. 18, 1969 K. D. BROWN 3,478,408

METHOD AND APPARATUS FOR FORMING HELICAL SPRINGS AND THE LIKE Filed Oct.21, 1965 6 sheets-Sheet 5 INVENTOR.

KENARD D. BROWN ATTORNEYS Nov. 18, 1969 K. D. BROWN 3,478,408

METHOD AND APPARATUS FOR FORMING HELICAL SPRINGS AND THE LIKE 6Sheets-Sheet 6 Filed Oct. 21, 1965 INVENTOR. KENARD D. BROWN ATTORNEYSUnited States Patent U.S. Cl. 29458 23 Claims ABSTRACT OF THE DISCLOSUREA method for producing a helical coil of wire comprises drawing a wirecontinuously across a deflector and pressing it into engagementtherewith to produce a curl in the wire about an axis on the same sideof the wire as the deflector and then guiding the Wire into a helicalcoil about a longitudinal axis. The longitudinal axis may be that of acylindrical tube about which the coil is wrapped. The method may furtherinclude passing the wire over spaced deflectors the first to bend thewire away from and the second toward the longitudinal axis.

An apparatus on which the method may be practical comprises a rotatablewire supply and forming assembly having a hollow center shaft throughwhich a plastic tubing or the like may be fed for wrapping with ahelical coil of wire. The wire is fed through a tool on the rotatingassembly and onto the tube about which the assembly is rotated. The toolcomprises spaced deflecting elements arranged first to bend the wireaway from the tube and then toward the tube. The tool rotates about thetube close to its surface and the bend away from the tube occurs nearerthe center of rotation than the subsequent bend toward the center. Theapparatus produces continuous lengths of helical wire wrapped tubingthewrapping may be made to lie merely in contact with the surface of thetubing or to grip it.

This is a continuation-in-part of copending application Ser. No. 225,559filed Sept. 24, 1962, now abandoned.

This invention relates to the manufacture of helically wound spring wireproducts and particularly to an improved method and apparatus forcontinuously forming helical springs and for Wrapping such springs ontubing or the like.

Many applications requiring helically wound spring wire make itdesirable to provide long or greatly extended continuous lengths of thehelical spring. For example, it is desirable to provide long continuouslengths of tubing having thereon a helical Wrapping of wire to provideincreased resistance to internal pressure and to external crushingforces, and it has been found diflicult to provide such wrapping in amanner such that it will remain in its required relationship to the tubewhen the tube is cut to desired lengths during installation or use. Inother applications of helical springs it is desirable to provide aninsulating or protecting coating on the spring which must be of uniformthickness and insulating quality. Various methods and apparatus havebeen proposed to overcome these problems but these have not been foundentirely satisfactory for all applications. Accordingly, it is an objectof the present invention to provide an improved method for manufacturinghelical springs in continuous lengths.

It is another object of this invention to provide an improved method formaking insulation coated helical springs.

It is still another object of this invention to provide an improvedmethod for forming a helical wrapping of reinforcing wire such as springwire in firm engagement about a tube or other cylindrical structure.

It is a further object of this invention to provide an lmprovedapparatus for forming helical wire springs and similar wire structures.

It is a further object of this invention to provide a simple andimproved apparatus for making insulation coated helical springs.

It is a still further object of this invention to provide an improvedapparatus for wrapping a helical layer of reinforcing wire on a tube orother cylindrical structure.

Briefly, in carrying out the objects of this invention in one adaptationthereof, a length of wire is first coated with a uniform layer ofplastic, such as nylon, or other tough insulating material. The wire isthen driven forward transversely toward the axis about which a helicalcoil is to be formed. At a desired radial distance from the axis thewire is bent through a slight S or ripple-curve away from and thentoward the axis and is thereby coiled about the axis; by rotating thewire about the axis as it is driven toward it, the coil may bemaintained stationary about the axis. By providing a cylindrical mandrelor body, such as a continuous plastic tube, the coil may be formed aboutthe body in continuous firm contacting engagement or if desired ingripping engagement provided that the body has a diameter somewhatgreater than that of the internal diameter of the coil if it wereallowed to form as a free sprmg.

The apparatus of this invention in one embodiment thereof comprises aforming unit rotatably mounted on a hollow cylindrical support andhaving a tool holding plate extending beyond the end of the support. Asupply spool of the plastic coated wire to be used is mounted for freerotation around the cylindrical support in a position to be fed to thecoil forming mechanism. The machine is arranged to drive the Wire towarda tool mounted on the holder and spaced radially from the axis ofrotation. The tool is arranged to provide a plurality of spaced steps ordiverter points which introduce an S-curve in the wire which bends firstaway then toward the axis and which produces the required circular turnof the helix. The tool holder and tool are rotated about the axis at arate correlated with the feed rate of the wire so that the coil isformed and retained stationary about the axis.

The features of noveltywhich characterize the invention are pointed outwith particularity in the claims annexed to and forming a part of thisspecification. The invention itself, however, both as to its method ofoperation and its organization together with further objects andadvantages thereof will be better understood upon reference to thefollowing description taken in connection with the accompanyingdrawings, in which:

FIG. 1 is a perspective view partly cut away showing a spring formingmachine embodying the invention;

FIG. 2 is an enlarged longitudinal sectional view of a portion of thedevice taken along the line 2-2 of FIG. 1;

FIG. 3 is an enlarged diagrammatic view illustrating the gearing fordriving the wire feed;

FIG. 4 is a side elevation view of a tube wrapping equipment providedwith a spring forming machine of the type illustrated in FIG. 1;

FIGS. 5 and 6 are side and front elevation views, respectively, of awire shaping tool for the machine of FIG. 1;

FIG. 7 is a perspective view of the tool illustrated in FIGS. 5 and 6;

FIG. 8 is an enlarged end view of the spring forming tool of theapparatus of FIG. 1;

FIGS. 9 and 10 are side and front elevation views, respectively, of aportion of a tool similar to that of FIGS.

5 and 6 provided with an attachment for controlling spacing of the turnsof the wire helix;

FIG. 11 is an enlarged top view of the attachment of FIGS. 9 and 10;

FIG. 12 is an enlarged view of the operating end of the tool of FIG. 8;

FIGS. 13 and 14 are rear elevation and side views, respectively, of theoperating end of a modified form of the tool;

FIG. 15 is an end view similar to FIG. 8 illustrating a modification ofthe apparatus of the invention;

FIG. 16 is a side elevation view partly in section and partly brokenaway of the tool holding assembly of FIG. 15;

FIG. 17 is an enlarged end view of the lower end of the tool illustratedin FIG. 15;

FIG. 18 is an enlarged end view similar to FIGS. 8 and 15 illustrating afurther embodiment of the invention;

FIG. 19 is an enlarged side elevation view of a portion of the assemblyof FIG. 18;

FIG. 20 is a sectional view of an extruding apparatus illustrating astep in one method of the invention;

FIG. 21 is a side elevation view partly broken away diagrammaticallyillustrating a modified form of winding equipment embodying theinvention; and

FIG. 22 is an end elevation view partly broken away and partly insection of a portion of the apparatus of FIG. 21 taken along the line2222 of FIG. 21.

Referring now to the drawings, the invention has been illustrated, byway of example, in FIG. 1 as embodied in a spring forming unit 10mounted on a rigid stand 11 having a base 12 and arranged to provide acoiled spring 13 wrapped tightly about a thin plastic tube 14 which isfed through a central passage in the unit 10. The assembly 10 includes acylindrical support 15 rigidly and securely attached to the base column11 and having a ring or sun gear 16 rigidly secured to its opposite end.A tool holding assembly 17 is mounted on a cylindrical shaft 18 forrotation within the cylindrical support 15. In order to facilitate therotation of the shaft 18 it is mounted in roller bearings 20 and 21 ateither end of the cylindrical support 15. The shaft 18 is provided witha pulley 22 which may be driven by a belt connected to a suitabledriving motor (not shown). The tube 14 on which the coil spring is to bewrapped passes through the shaft 1 8 and is freely slidable axially ofthe shaft on inner rings 23 and 24 of ball bearing assemblies 25 and 26mounted at respective ends of the shaft 18, the assembly 26 being shownin FIG. 2.

In order to provide a supply of the wire from which coiled spring is tobe formed, a spool 28 is mounted about the support 15 on ball bearingassemblies 29 and 30 so that the spool is free to rotate about thesupport 15. The wire is fed to a wire drive mechanism 31 from the spool28 as indicated at 32, the wire portion 32 passing from the spoolthrough an eye 33 at the end of a bracket 34 rigidly attached to thetool holder assembly 17.

The drive assembly 31 for the unit is arranged to force the wire throughtwo sets or pairs of rollers 35 and 36 and thence through a tool 37which forms the wire to provide the coil 13, the wire passing from thetool 37 in a low loop 38 which is of a radius of curvature such that itfalls into place about the tube 14 and grips the tube tightly. The wireis formed by the tool 37 so that if the tube were not present it wouldbe formed as a free coil of a diameter slightly less than that of theexternal diameter of the tube. In some applications of this machine andprocess the wire is bent so that it just fits about the wall of thetubing, its internal helix diameter being essentially the same as theexternal diameter of the tube.

The driving wheels 35 and 36 are connected to be driven from a planetgear 40 which is mounted on a shaft journaled in the plate or toolsupport 17 and engages the sun gear 16 so that as the shaft 18 isrotated the gear 40 is driven at a rate determined by the ratio of thepitch diameters of the gears 16 and 40. The pairs of gears for drivingthe respective pairs of drive wheels 35 and 36 are arranged as shown inFIG. 3, both pairs of gears being driven from a driving pinion 41 whichis connected directly to the gear 40 through its shaft 42.

It will now be seen that the gears of the pairs 35 and 36 are rotated sothat the driving wheels associated therewith are driven in pairs in thesame direction. Thus a wire passing through the pairs of drive wheels,as indicated by the arrow in FIG. 3, will be driven from left to right.7

The wire 32 on the spool 28 may be either bare or coated; however, inthis example it is illustrated as coated, it having been formed byproviding a uniform coating of a tough smooth cover such as nylon, thecovering being formed to a substantial thickness. For example, the covermay have a thickness of the order of one-fourth the diameter of thewire. The thickness of the covering depends upon the material used andis not critical; however, it is selected to provide adequate insulationor adequate abrasion resistance of the wire and is made of a materialand of a thickness sufficient to assure its being maintained intact anduninjured throughout the operations of the forming equipment. Not onlydoes the covering provide the desired protection of the wire, but italso serves as a lubricant during the passage of the wire through theforming tool 37. The pairs of drive wheels 35 and 36 urge the wiretoward the tool 37 and force it through the tool to alter itsconfiguration and form the coil in a manner to be described hereinafter.

At the same time that the wire is being fed toward the tool 37, theentire assembly is of course being rotated by rotation of the shaft 18.The rate of feeding of the wire is selected with respect to the speed ofthe shaft 18 so that the wire is wrapped around the tube 14 at a ratesuch that the tube and wire coil 13 do not rotate but remain stationaryabout their longitudinal axis during the operation of the equipment;thus the tube need only be moved axially as the coil is formed. Thisprovides a secure and firm pressure resisting wrapping about the tubing14 and continuous lengths of tubing may be passed through the equipmentand wrapped with wire. Furthermore, the wire will remain in place at theend of the tubing and also, should the tubing be cut into separatelengths, the wire in each length will remain in place fitting closelyabout and, if desired, tightly gripping the exterior walls of the tube.If the tubing is omitted the wire will be formed in a continuous helicalfree coil of a diameter which is normally somewhat less than that of thetubing; thus a plastic coated spring may readily be formed to thediameter selected by the position of the tool 37.

When bare spring wire is employed, it may be desirable to provide alubricant to facilitate the forming operation and assure uniform coilingof the final product. Although plastic coatings are desirable for a widerange of applications, various other coatings lend themselves to use inthis method of forming spring and other wire structures. For example,metallic coatings and metalimpregnated plastic coatings may be employed.

The helical wire coil or spring forming assembly or unit 10 illustratedin FIG. 1 and as just described may be incorporated in an equipment forproducing continuous helical coil reinforced tubing as shown in FIG. 4.In this figure the drive pulley 22 has been shown connected by a belt 44to be driven by an electric motor 45 and the reinforced tubing, afterpassing from the unit 10, has been shown as drawn through a drive roll46 and idler roll 47 onto a collecting drum 48 which is mounted forrotation in a supporting base 50 and is driven by a suit able motor (notshown). The drive roll 46 is driven by a motor 51 mounted in a base andsupporting structure 52. The motor drives the roll 46 through a belt 53and the idler wheel 47 is mounted on top of the wheel 46 in position toengage the tubing 13 and press it downward to maintain it in gooddriving engagement with the drive wheel.

The configuration of the tool 37 is clearly shown in FIGS. 5, 6 and 7.The tool as illustrated comprises a main body portion 54 and a shank 55of reduced cross section which is provided with an elongated slot 56having sides parallel to the sides of the tool. The lower end of thetool is rounded at one side as indicated at 57 and has a short extension58 at its other side. The extension 58 is formed with a straight lengthof groove or guide 60 having a cross-sectional diameter slightly greaterthan that of the wire to be used with the tube. As illustrated thegroove lies closely adjacent the lower end of the tool and only a thinstrip or section of the tool, indicated at 61, extends beyond the groove60. The groove 60 opens forward and hence axially of the shaft 18 andits curved or circular cross section, as indicated in FIG. 5, is suchthat the wire is retained in position against displacement from thegroove axially of the shaft 18. The slot 56 is provided in order that abolt, indicated at 62 in FIG. 1, may be employed to clamp the toolrigidly to the tool holder 17.

The arrangement of the tool and its position during operation may morereadily be understood from FIG. 8 which is an enlarged view with thecurvature of the wire passing through the tool somewhat exaggerated forpurposes of illustration.

As clearly shown in FIG. 8, the tool 37 is mounted so that the left-handedge of the portion 61 is closely adjacent and in some applicationstouching the outer surface of the tube 14. This brings the entrance edgeof the groove 60 close to the tube. The wire 32 is fed or forced forwardby operation of the pairs of rollers 35 and 36, the pair 36 being shownin FIG. 8, and as the wire moves forward -it strikes the near or lowerrounded edge portion 57 of the tool and enters the groove 60 and iscurved downwardly over the lower edge portion or knee 57 so that ittakes a curved or bowed configuration about as shown by the portion 65.As previously stated, the groove 60 is of a width slightly greater thanthe diameter of the wire 32 and the configuration of the wire as itpasses through the tool is in S or reentrant form, the wire moving fromthe knee 57 to the bottom of the rear corner or leaving edge of thegroove 60, presents a small radius or edgelike shoulder and produces areverse bend as indicated at 66. The bend 66 has been shown of somewhatexaggerated curvature, its radius having been shortened for emphasis;however, it will be noted that it is in a direction such that the wiretends to coil about the tube 14 as indicated. The bend 66 is produced atthe edge or shoulder of the portion 61 and results from plasticdeformation at the edge, the elastic limit of the wire being passed atthis edge due to the pressure of the wire against the edge. The changein curvature is abrupt at the edge and the wire curves outwardly awayfrom the shoulder in a curve which then turns back toward the tube 14 onwhich it is being wrapped. The forming pressure against the edge 61 isapplied by the urging of the Wire against the shoulder by the portion 57on one side and the engagement of the wire and the tube 14 on the otherside. The angle of the tool 37 causes a torque to be exerted on the wirebetween the shoulders 57 and 61. 'It will be observed that the pressureexerted between the shoulder 61 and the wire may be changed by changingthe angle of the tool 37 to change the position of the line between theshoulders 57 and 61. Thus, the degree of bending of the wire may beadjusted.

Under some conditions of operation when relatively large wires are beingemployed, the wire after bearing on the rounded edge 57 may be forcedagainst the rear or entrance edge of the groove 60 and thereby be curvedupwardly away from the rear or departing edge of the strip 61 and mayengage the upper corner of the tool 37 opposite the curved edge 57 whichprovides a guiding and curve modifying function which may facilitate theoperation of the tool to guide the wire into the desired helical coilconfiguration. It will be understood that for this type of operation itmay be desirable to change the relative proportions of the two shouldersor parts of the tool to secure effective use of the edge or shoulderportions in the manner just described. A tool for more effectivelysecuring'these functions is shown in the drawings in FIG. 15 anddescribed below.

The internal diameter of the free coil formed by the tool without thetube 14 present would be of no greater than and normally would besomewhat smaller than the outer diameter of the tube, and, as aconsequence, the coiled wire lies in engagement with the tube andnormally grips the tube tightly as it moves along. The wire may be laidin closely adjacent coils, the coils touching each other as they arewound around the tube, or by increasing the rate of movement of the tubeit may be spaced at a predetermined pitch selected by adjustment of theaxial speed of the tube.

The driving engagemnt of the rollers 35 and 36 on the wire 32 may beadjusted by a nut 68 which varies the position of a movable element 69on which the upper rollers are mounted. The range of this adjustment isrelatively small, it being limited by the range of radial movementafforded by the gear teeth for driving the rollers, a certain relativemovement of the teeth being possible without interfering with theiroperation.

It will be understood that the diameter of the coil formed by applicantsmethod as illustrated in the operation of the device shown in FIG. 8 maybe varied by employing a tool 37 having different relative positions ofthe two contact points which the wire makes with the tool and bychanging the angle of the tool to vary the point of engagement of thewire with the tube and, also, by changing the dimensions of the groove60 to accommodate the particular size of Wire to be employed. The tube,in effect, acts as a third stop or control element for determining thefinal configuration of the wire.

Apparatus embodying the invention as illustrated has been operatedcontinuously both with and without the use of a tube 14 and has beenemployed to make both the reinforced tubing and the springs producedwhen the tubing is omitted. The wrapping on the tubing and the coils ofthe springs were of uniform diameter and spacing regardless of thelength of the coil or spring produced. It was found that the spring wirecould be wrapped continuously onto the tubing in gripping engagementwithout exceeding the elastic limit of the wire material after it leavesthe forming tool and winds around the tube.

When employing the method of this invention for producing coiled helicalsprings, it may be desirable to form the springs with a predeterminedspacing between adjacent turns of the coil. For the purpose of producingsprings in this manner as distinguished from tightly coiled springs, atool as indicated in FIGS. 9, 10 and 11 may be employed. This tool is ofthe same construction as that of the tool of FIGS. 5, 6 and 7 with theaddition of an attachment 70 which is secured to the lower end of thetool by a suitable machine screw 71 as illustrated. The attachment 70closes the open face of the groove 50 and extends beyond the tool asubstantial distance toward the axis of rotation. The attachment 70 is awedge, as clearly indicated in FIG. 11, and as the tool moves aboutthe'axis the coil formed by the operation of the tool is caused to passon the outside of the wedge 70 so that the coil is separated as it isformed and the pitch of the turns is predetermined by the dimensions ofthe attachment 70, each turn of the coil being forced away axially fromthe next and not returning to a position of engagement with adjacentcoils.

It has been found that a tool of the construction of the tool 37 may beemployed effectively for the coiling or wrapping of wires of relativelysmall diameter; for example, a wire having a diameter of less thanone-fourth of that illustrated in FIG. 8 may be wound eifectively abouta tubing by operation of the apparatus. For this type of application theangle of the tool is adjusted by rotation of the tool about the pivotbolt 62 so that effective bending and coiling of the wire may beaccomplished.

When wires of the size illustrated in FIG. 8 are employed and passthrough the tool along the curve indicated, the wire is pressed firmlyagainst the leaving edge of the tool portion 61 and this pressure tendsto produce a momentary depression in the surface of the wire as it movesin frictional engagement with the edge. In FIG. 12 the end of the tool37 is illustrated in an enlarged view, the portion of the wire passingthrough the tool in an elongated S-curve as shown and for this operationbearing solely against the rounded corner 57 and the leaving edge of thetool portion 61, the wire tending to be indented temporarily at the zoneindicated at 75 and being plastically deformed at this point. Thefrictional engagement produced by the downward pressure of the wireagainst the rounded right-hand end of the section 61 of the toolproduces the curving of the wire indicated at 66 wherein the wire iscurved toward the axis about which it is to be coiled, normally at aradius somewhat less than the tubing or other cylindrical body aboutwhich it is to be wound. This curve, as stated before, has been somewhatexaggerated in FIGS. 8 and 12, the reverse curve occurring immediatelyupon the passing of the wire over the leaving edge of the tool strip 61.

A tool such as the tool 37 may be constructed to carry a plurality ofwires which are then Wrapped in adjacent helical configuration about atubing such as the tube 14. The working end of a tool of this type isshown in FIGS. 13 and 14 which illustrate a tool 76 provided with aportion 77 of reduced cross section similar to the extension 58 of thetool 37. The tool 76 provides a rounded shoulder or stop 78corresponding to the shoulder 57 of the tool 37, and the wire guidecorresponding to the groove 60 of the tool 37 comprises a hole oropening 80 extending through the extension 77 and having its lower wallportion provided with two guide grooves 81 and 82 for receiving twowires to be passed through the tool in parallel. Tools providing agreater number of such guide grooves may, of course, be provided if morethan two wires are to be wrapped simultaneously about a cylinder ormandrel.

The operation of the tool of FIGS. 13 and 14 is essentially the same asthat of the tool 37 previously described, the two wires being driventhrough the tool together and first engaging the rounded edge 78 andthen passing through the grooves 81 and 82 and over the far or leavingedge of the recess 80.

FIG. illustrates a modified form of the tool which is arranged tofacilitate the adjustment of the stop or guide points or shoulders toprovide the adjustment required for various sizes of wire and diametersof the coil to be formed. In this figure parts corresponding to theparts of the apparatus shown in FIG. 8 have been designated by the samenumerals with the addition of the suffix a. The tool 37a is mounted on aplate 83 which extends radially outwardly in a plane transverse to theaxis of the coil or spring to be formed. The plate 83 is mounted on thetool holding assembly 17a on a ring 84 concentric with the central axisof the assembly and formed in the face of the tool support as indicatedat 85 in FIG. 16. The tool 37a is provided with a slot 56a through whicha mounting bolt 62a is passed. This bolt also passes through a circularopening 86 in a plate 87 which is secured to the plate 83 when the tool37a is bolted against the plate. The plate 87 carries a shoulder or bar88 which terminates in a rounded guide stop or shoulder 90.

It will now be seen that because of this mounting the tool 37a and plate87 may be adjusted with respect to one another and with respect to theplate 83. In order to effect angular adjustment of the tool 37a aboutthe pivot bolt 62a, a pair of adjusting screws 91 and 92 are providedwhich are threaded in lugs 93 and 94, respectively, rigidly attached tothe plate 83. The wire to be coiled, indicated at 32a, is passed throughthe tool 37a in a manner essentially the same as indicated for the wire32 in FIG. 8 and then the curved portion 66a as it leaves the toolengages the shoulder and its curve is modified to conform to a requiredcoil diameter. The shoulder 90 constitutes a guiding element andperforms the function of cooperating with the shoulder 57a and urgingthe wire against the edge of shoulder of portion 61a of the tool 37a.Thus the shoulder 90 performs the functions of the tube 14 in theembodiment of FIG. 8. It has been found that this form of the tool whenadjusted to the size of wire and required curvature of the coil providesaccurate formation of free coils or springs, and the assembly asillustrated in this figure is provided with a circular closure plate 97which covers the central passage through the machine. This plate may bemoved outwardly to the left as viewed in FIG. 16 to provide a short orstub mandrel about which the initial coil or coils of the spring areformed. For some applications the use of the sub mandrel has been foundto facilitate the securing of an accurately formed spring.

The adjustment of the tool assembly to the required wire size isfacilitated by the mounting arrangement of the ring 84 in the groove 85so that the angle of the plate 83 may be adjusted with respect to thefeed fire 32a. When the desired angle has been determined the ring maybe locked in place by tightening bolts 95 threaded in the assembly 17aand which press washers 96 against the ring.

FIG. 17 is an enlarged end view of the tool 37a illustrating wirepassing through the tool. In this figure the tool is shown in sectionand it can be seen that the bottom wall portion of the wire passage 60ais formed to provide a section which is of decreasing thicknessrearwardly. The tool 37a has been illustrated as provided with a closedwire passage similar to the passage in the tool of FIGS. 13 and 14rather than the open passage of the tool 37 of FIG. 8. The wire passingthrough the tool 37a first engages the rounded rear shoulder of the toolindicated at 57a and then the forward edge or shoulder of the portion61a indicated at 97. The action of the wire and the change in itsconfiguration are essentially the same as that effected by operation ofthe tool 37 of FIG. 8.

Another arrangement of the bending tool of this invention is illustratedin FIGS. 18 and 19. In these figures parts of the assembly correspondingto parts of the assembly of FIG. 8 have been designated by the samenumerals with the addition of the suffix b. In this tool assembly twostop members or pins 100 and 101 are provided and are rigidly mounted ona tool assembly comprising a plate 102 mounted on a ring 103 in a mannersimilar to the mounting of the plate and ring 83 and 84 of FIG. 15. Theplate 102 carries an adjustable bar 104 which carries the stop 100, andthe stop 101 is secured directly to the plate 102 in a position adjacentthe edge of the central opening within which the tube 14b is carried.

A wire indicated at 3217 is passed through the driver assembly 36b andmoves through a curved portion 6512 against the stop 100 which act inthe same manner as the shoulder 57 of FIG. 8. It is then carried forwardto pressing engagement with the stop or shoulder 101 where it is bentoutwardly in a manner similar to the wire passed through the assembly ofFIG. 8 and forms a curve as indicated at 6612. The constructionillustrated in FIGS. 18 and 19 provides a simplified arrangement whichhas been found effective for use particularly when larger diameters ofwire are to be wound.

In all of the tool assemblies illustrated it may be desirable to providea coating of smooth tough plastic material, as indicated before, andFIG. 20 indicates a type of extruding head suitable for this purpose. Inheads such as illustrated there is provided a heavy metal body indicatedat 106 and in which a fluid material passage 107 is provided incommunication with a tapered or conical 9 chamber 108 in which a wirefeeding guide 109 is centered. A wire 110 is fed through the guide 109and the plastic material extruded onto the wire to form a layer asindicated generally at 111.

This type of extrusion apparatus is capable of producing a very smoothplastic coating on a wire, the coating being cured as it leaves the dieand before it is coiled on a suitable reel. The thickness of the coatingmay be varied by changing the extruding die indicated at 112, andvarious diameters of wire may be employed, a guide 109 having a suitablediameter passage for the wire being selected for this purpose.

While the wire wrapping or coiling devices described above have all beenillustrated with arrangements for moving the tool about the tubing to bewrapped or spring to be formed so that the tubing or spring does notrotate, the apparatus of this invention is also useful for wrapping ormandrels, tubing or conduit wherein the tubing is rotated while the toolremains in a stationary position.

- Apparatus such as this has been found useful for wrappingpredetermined lengths of large diameter tubing or conduit and anapparatus for this purpose is diagrammatically illustrated in FIGS. 21and 22.

In these figures a tubing or conduit indicated at 115, and which is tobe wrapped with a wire to provide a wrapped conduit as indicated at 115'to the left of a tool 116, is mounted in a hollow-shafted lathe having adriving head 117 through which the finished product passes and havingone or more rests 118 for holding the tubing 115 in alignment. The tool116 is mounted on a carriage or tool carrier 120 which is mounted formovement along a bed 121 on rails or guides 122. The carrier is providedwith an extension 123 which is mounted for sliding movement along thelathe bed indicated at 124. The carrier 120 is provided with a toolmounting bracket or plate 125 on which the tool 116 is mounted and withrespect to which it may be adjusted by loosening a bolt 126 in the samemanner as the adjustment of the bolt 62, for example, in FIG. 8.

The wire to be wrapped about the tubing 115 is carried on a reel 127mounted on bearing brackets 128 and 129 secured to the carrier 120, thereel having been broken away in FIG. Q1 to show the tool assembly. Thewire after passing from the reel goes through a guide loop 130 andthence onto the tool, it being drawn through the tool by rotation of thetubing 115 effected by rotation of the lathe head 117. The carrier 120is moved along the bed 124 at a rate to secure the required positions ofthe turns of the wrapping 115, the movement of the carriage beingeffected by operation ofa longitudinal screw 131 in a manner well knownin the lathe and machine tool art.

The mechanisms of FIGS. 1 and 21 are illustrative of two methods ofapplying the driving forces to the wire, the apparatus of FIG. 1 drivingthe wire into the tool and that of FIG. 21 drawing it through the toolby rotation of the tubing.

It will be apparent from the foregoing that this invention provides asimple and effective arrangement for forming wire in helical coils andparticularly for wrapping a helical winding about a tube or conduit in amanner such that the wire remains in position and does not tend to bedisplacedeven though the conduit is cut or broken. The wire may bewrapped tightly in gripping engagement about the conduit or, if desired,may be wrapped so that it contacts the surface of the conduit but doesnot grip the conduit. The type of wrapping to be secured, of course,depends upon the applications for which the wrapped tubing or conduit isintended, and the degree of gripping engagement of the wire and thetubing may be; varied depending upon the use or application of theconduit. For example, a tighter gripping wrapping may be desirable whenthe tubing is required to resist high pressures.

The method and apparatus of this invention have a further advantage inthat wire regardless 'of diameter may be coiled tightly to form a springor helical wrapping or may be wrapped tightly about a cylindrical formsuch as a tube without damaging the wire. For example, a large diameterwire may be coiled about a small tube without substantial expansion orrotation upon release of the wire and without injury to the wire whichmight otherwise decrease its strength and render it ineffective for itspurpose, and so-called normalizing becomes unnecessary.

While the method of this invention has been described in connection withthe operation of specific forms of apparatus embodying the invention,various other applications and modifications of the method of theapparatus will occur to those skilled in the art. Therefore it is notdesired that the invention be limited to the specific detailsillustrated and described and it is intended by the appended claims tocover all modifications which fall within the spirit and scope of theinvention.

I claim:

1. An apparatus for the continuous production of helically coiled springwire or the like which comprises a unit mounted for rotation about afixed axis, said unit comprising a tool holder mounted for rotationabout said axis in a plane normal thereto, a wire bending tool on saidholder and spaced radially from said axis, means on said holder fordriving wire into said tool during rotation of said holder about saidaxis, and driving means for rotating said unit about said axis, saidtool including means for producing an S-curve in the wire during passagetherethrough, the first turn of the S being away from said axis and thesecond turn about a center near said axis, said tool being formed toprovide a short slot for the wire extending along an axis substantiallytangential to the path of rotation thereof and having a width slightlygreater than the diameter of the wire to be used therewith.

2. An apparatus for the continuous production of helically coiled springwire or the like which comprises a unit mounted for rotation about afixed axis, said unit comprising a tool holder mounted for rotationabout said axis in a plane normal thereto, a wire bending tool on saidholder and spaced radially from said axis, means on said holder fordriving wire into said tool during rotation of said holder about saidaxis, and driving means for rotating said unit about said axis, saidtool including means for producing an S-curve in the wire during passagetherethrough, the first turn of the S being away from said axis and thesecond turn about a center near said axis, said wire driving means isconnected to be driven by said means for rotating said unit.

3. An apparatus for the continuous production of helically coiled springwire or the like which comprises a unit mounted for rotation about afixed axis, for said unit comprising a tool holder mounted for rotationabout said axis in a plane normal thereto, a wire bending tool on saidholder and spaced radially from said axis, means on said holder fordriving wire into said tool during rotation of said holder about saidaxis, and driving means for rotating said unit about said axis, saidtool including means for producing an S-curve in the wire during passagetherethrough, the first turn of the S being away from said axis and thesecond turn about a center near said axis, said wire driving means andsaid unit driving means being connected by a planetary gearing includinga fixed sun gear and a planet gear and said planet gear being drivenaround said sun gear with rotation of said unit and said wire drivingmeans being connected to be driven by said planet gear.

4. An apparatus for the continuous production of helically coiled springwire or the like as set forth in claim 1 including a guide deflectormounted on said unit and spaced from said slot on the side thereoftoward said wire driving means for producing an initial bend of the wireaway from said axis.

5. An apparatus for the continuous production of helically coiled springwire or the like which comprises a unit mounted for rotation about afixed axis, said unit comprising a tool holder mounted for rotationabout said axis in a plane normal thereto, a wire bending tool on saidholder and spaced radially from said axis, means on said holder fordriving wire into said tool during rotation of said holder about saidaxis, and driving means for rotating said unit about said axis, saidtool including means for producing an S-curve in the wire during passagetherethrough, the first turn of the S being away from said axis and thesecond turn about a center near said axis, said tool comprising threeguide deflectors spaced from one another tangentially of the path ofrotation and the outer two of said deflectors being spaced radiallyfarther from said axis of rotation than the intermediate one of saiddeflectors.

6. The apparatus of claim including means for adjusting the positions ofsaid guide deflectors with respect to one another and with respect tosaid axis of rotation.

7. An apparatus for forming a helical coil of spring wire or the likeabout a predetermined axis comprising a rigid shoulder, means forholding said shoulder facing radially outwardly of said axis at aposition spaced radially from said axis and closely adjacent the outercircumference of the coil to be formed, means for guiding a wire to becoiled through a plane transverse to said axis and over said shoulder,means for moving the wire continuously through said guiding means andover said shoulder and for pressing the wire against said shoulder witha force sufficient to deform the wire plastically at said shoulderwhereby the wire leaves the shoulder in a curve extending radiallyoutwardly from said shoulder in said plane and about an axissubstantially parallel to said predetermined axis, and means forengaging the wire after its passage over said shoulder for urging ittoward said predetermined axis and for bringing the axis of curvature ofthe wire into coincidence with said predetermined axis.

8. The apparatus of claim 7 including means for adjusting the positionof said shoulder with respect to said guiding means and for changing theposition about said axis of the line between said guiding means and saidshoulder.

9. The apparatus of claim 7 wherein said engaging means comprises acylindrical body mounted with its axis coinciding with saidpredetermined axis for relative movement along said predetermined axiswith respect to said guiding means and wherein said curved wire isguided about said body and into wrapping engagement with the surfacethereof.

10. The apparatus of claim 7 wherein said wire engaging means comprisesa wire bending deflector spaced from said shoulder for pressingengagement with the outer side of the wire whereby the wire first passesthrough said guiding means and over said shoulder and is then engagedand bent to bring the axis of its curvature into substantial coincidencewith said predetermined axis.

11. The apparatus of claim 10 including means for adjusting the positionof said shoulder and said bending deflector with respect to one anotherand with respect to said axis.

12. An apparatus for the continuous production of helically coiledspring wire or the like which comprises a rigid base, a hollowcylindrical support rigidly attached to said base, a drive shaft mountedwithin said support and extending beyond one end thereof, a tool holdermounted on said one end and rigidly secured thereto, a wire forming toolon said holder, power means on said holder for driving a wire intoengagement with said tool for forming the wire in a helical coil, meansfor rotating said shaft, and gearing means connecting said shaft andsaid power means for actuating said power means whereby said wire isconcurrently driven into engagement with said tool and is rotated aboutthe axis of said support, the

rate of rotation of said shaft and the driving rate of said wire beingcoordinated to maintain the finished coil substantially stationarywithout rotation about the axis of said shaft.

13. An apparatus for the continuous production of helically coiledspring wire or the like as set forth in claim 12 including a wire supplyspool mounted on the outside of said support for free rotation withrespect thereto, and means for feeding wire from said spool into saidpower means.

14. An apparatus for the continuous production of helically coiledspring wire or the like as set forth'in claim 12 wherein said shaft ishollow and including bearing means within said shaft for mounting a tubefor free rotation within said shaft and for free axial movementtherethrough, said bearing means positioning said tube concentricallywith respect to the axis of said shaft.

15. The method of producing a helical coil of spring wire or the likewhich comprises providing a shoulder of rigid material, holding a lengthof wire to be formed transversely of the shoulder and while moving thewire and shoulder lengthwise of the wire with respect to one anotherurging the wire against the shoulder with sufficient force toplastically deform the wire at the shoulder such that on leaving theshoulder the wire bends abruptly away from the shoulder and forms in acurve about an axis spaced from the shoulder on the side of the shoulderremote from the side of the shoulder in engagement with the wire, andguiding the curved wire into a coil having its axis substantiallyparallel to that of the curve of the wire and its outer circumferenceclosely adjacent to the shoulder.

16. The method of claim 15 wherein the shoulder is of relatively smallradius of curvature as compared with the diameter of the helical coil tobe formed and the wire is moved over the shoulder in frictionalengagement therewith.

17. The method of claim 15 including the steps of providing a secondshoulder and a wire engaging element for the guiding of the curved wireand holding the second shoulder ahead of the first shoulder on theopposite side of the wire and wherein the urging of the wire against thefirst shoulder is effected by locating the second shoulder and theguiding element in positions on respective opposite sides of the firstshoulder along the wire and engaging the wire on the side of the wireopposite the side engaged by the first shoulder.

18. The method of claim 17 including the step of adjusting the pressurebetween the wire and the first shoulder by changing the angular positionof the line from the first shoulder to the second shoulder.

19. The method of claim 15 including the steps of rotating said shouldercontinuously about the axis of the coil and moving the wire over saidshoulder at a rate to prevent rotation of the coil being formed.

20. The method of wrapping a helical coil of spring wire or the likeabout a cylindrical body in engagement therewith which comprisesproviding a cylindrical body, providing a shoulder of rigid material andpositioning it closely adjacent the outer surface of the body inalinement with the longitudinal axis of the body and facing away fromthe body, passing the wire over the shoulder transversely of thelongitudinal axis of the body and onto the body and while rotating thebody and shoulder with respect to one another urging the wire againstthe face of the shoulder with sufiicient force to plastically deform thewire at the shoulder whereby on leaving the shoulder the wire bends in acurve opening toward the body and extending radially outwardly beyondthe shoulder and back toward the body, wrapping the wire about the bodyduring the relative rotation thereof with respect to the shoulder, andmoving the body axially with respect to the shoulder to form a helicalcoil.

21. The method of claim 20 including the initial step of providing asmooth, uniform coating of plastic mate- 13 rial on the wire and whereinthe material of the surface of the body is plastic having physicalcharacteristics essentially the same as those of the coating on thewire.

22. The method of claim 20 including the step of preventing rotation ofthe body while rotating the shoulder at a uniform rate about the bodyand maintaining the supply of the wire at a rate just suflicient to wrapthe wire about the body whereby the body moves forward axially with thecoil in engagement therewith and without rotation.

23. The method of forming a helical coil of spring wire or the likeabout a cylindrical form as set forth in claim 20 including the step ofeffecting axial movement of the tube at a rate to form the adjacentturns of the helical coil in engagement with one another.

References Cited UNITED STATES PATENTS 6/1913 Byrnes 29-173 Sleeper72-66 Ekstedt 72-135 Owston 72-66 Pierce 7'2-135 Kirchner 72-135 Giros72-135 Jaycox 72-66 Chenex et al.

Montignot 72-135 Heckethom et al.

FOREIGN PATENTS Great Britain.

15 CHARLIE T. MOON, Primary Examiner US. Cl. X.R.

